Issue 24

G. Cricrì, Frattura ed Integrità Strutturale, 24 (2013) 161-174; DOI: 10.3221/IGF-ESIS.24.17

C ONCLUSIONS complete procedure for the R-curve calculation has been presented, tested on a MT test specimen simulation reproducing a widely used aeronautical alloy, 2024A-T351, which gives results in a very good agreement with the experimental tests. The algorithm was based on the local form of the Gurson – Tvergaard –Needleman damage model and, differently from the purely phenomenological approach that is usually employed to calculate all the model parameters, it uses a preliminary RVE definition, partially based on microstructural information on the material, to determine most of the continuum-scaled model. In order to enrich the original damage model also the defect size distribution has been considered. Only few parameters are tuned on the basis of an experimental test: they are the nucleation parameters f N ,  N , S N . They are related to the material behaviour, nor to the geometry of the test specimen. For this reason, they can reasonably be determined with a single test result, as is done in the present work, and the same values can be used for different geometries, as the design process requires. [1] R. Citarella, G. Cricrì, Advances in Engineering Software, 40 (2009) 363–377. [2] Office of Aviation Research - Residual Strength Test on Stiffened Panels With Multiple-Site Damage, technical report, Washington, D.C. 20591 [www.tc.faa.gov/its/act141/reportpage.html]. [3] T. V. Pavankumar, M. K. Samal, J. Chattopadhyay, B. K. Dutta, H. S. Kushwaha, E. Roos, M. Seidenfuss, Int. J. of Pressure Vessels and Piping, 82 (2005) 386. [4] B. Dodd, B. Yilong, Ductile Fracture and Ductility, Academic Press Inc. Ldt., Orlando, Florida, (1987). [5] M. Li, Int. J. Mech. Science, 42 (2000) 907. [6] L. Xia, C. Fong Shih, J. W. Hutchinson, J.Mech. Phys. Solids, 43(3) (1995) 389. [7] L. Xia, C. Fong Shih, J.Mech. Phys. Solids, 43(2) (1995) 233. [8] L. Xia, C. Fong Shih, J.Mech. Phys., Solids, 43(12) (1995) 1953. [9] L. Xia, C. Fong Shih, J.Mech. Phys., Solids, 44(4) (1996) 603. [10] C. Ruggieri, T. L. Panontin, R. H. Jr. Dodds, Int. J. of Fracture, 82 (1996) 67. [11] L. Malcher, F. M. Andrade Pires, J. M. A. César De Sá, Int. J. of Plasticity, 30-31 (2012) 81. [12] A. S. Gullerud, K. C. Koppenhoefer, A. Roy, R. H. Jr. Dodds. WARP3D–Release 13.9 - Department of Civil Engineering, University of Illinois at Urbana–Champaign Urbana, Illinois, (2000), ISSN: 0069–4274. [13] H. L. Schreyer, M. K. Neilsen, Int. J. Numer. Methods Engrg., 39 (10) (1996) 1721. [14] G. Cricrì, R. Luciano, Simulation Modelling Practice and Theory, Elsevier, 11 (2003) 433. [15] G. Cricrì, M. Perrella, C. Calì, Composites Part B: Engineering, 45(1) (2013) 1079. [16] S. D’hers, E. N. Dvorkin, In: Mecánica Computacional, Buenos Aires, Argentina, XXIX (2010) 5189. [17] M. K. Samal, M. Seidenfuss, E. Roos, B. D. Dutta, H. S. Kushwaha, In: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science (2009) 223. A R EFERENCES

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